When a patient's knee is severely damaged, such as by osteoarthritis, rheumatoid arthritis, or post-traumatic arthritis, it may be desirous to repair and/or replace portions or the entirety of the knee with a total or partial knee replacement implant. Knee replacement surgery is a well-tolerated and highly successful procedure that can help relieve pain and restore function in injured and/or severely diseased knee joints.
In a typical knee surgery, the surgeon will begin by making an incision through the various skin, fascia, and muscle layers to expose the knee joint and laterally dislocate the patella. The anterior cruciate ligament may be excised and/or the surgeon may choose to leave the posterior cruciate ligament intact—such soft tissue removal often depends on the surgeon's preference and condition(s) of the ACL/PCL. Various surgical techniques are used to remove the arthritic joint surfaces, and the tibia and femur are prepared and/or resected to accept the component artificial implants.
Preparing the surface of the tibia often requires that the surgeon resect the articular surface of the bone to receive an implant over the resected surface. The resection can include specific depths of cut(s), posterior slope(s), varus/valgus angle(s), and/or axial alignment(s) that can be unique to every patient. The specific dimensions and/or measurements desirably ensure proper positioning of the artificial joint component assembly, and accurate guiding and cutting of the tibial plateau is important to achieve the most accurate and best fit of the artificial implant components.
Traditionally, a surgeon has two options to help them prepare the tibia. The surgeon may select the traditional “freehand” method, or he/she may choose a set of surgical instruments that will assist with positioning, resection and alignment. The “freehand” method usually involves standard surgical tools available in the operating room (OR) during surgery, such as osteotomy drills and calipers for measuring. The procedure, preparation, alignment and/or resection may be more or less accurate, depending on the level of the skill and/or ability of the surgeon. Where surgical guide tools are chosen, the surgeon may employ a standard sized saw guide block or other resection guides, which desirably assist with the critical cuts required in the tibial plateau. A saw guide block or resection guide can first be attached to the patient in various ways, and then an alignment device can be used to provide a desired alignment. Once the resection guide is aligned, it can be temporarily fixed in place on the anterior side of the tibia, and the alignment device removed to allow the cutting or resection operation. While the use of such standard sized guide blocks or resection guides can improve the surgical procedure, they may not provide sufficient fine adjustments for cutting depth and/or slope, may be bulky, and may not be easy to use. The misuse or non-use of such devices can result in improper depth of cut, improper posterior slope, malalignment of varus/valgus angle(s), and poor axial alignment that may contribute to poor artificial implant positioning, instability of the joint, and poor surgical outcomes.
As a result, it has been recognized that it would be desirable to provide a more effective system of guides, tools, instruments and methods to facilitate a high degree of success in the preparation of the tibial plateau to receive an artificial joint.